Abstract: To realize a pattern detection apparatus enabling to set a hardware resource holding a detection pattern and a detection position adequately and enabling to reduce overhead of processing after pattern detection in the case of performing pattern detection in response to a comparison result of detection target data and an entry pattern. The pattern detection apparatus compares an entry pattern (ETP) held by an entry pattern holding unit (124) with data inputted from the outside of the pattern detection apparatus in a comparator 122, and outputs a hit signal (HIT) showing agreement when agreeing. A flag holding unit (126) outputs a held flag signal (FLG) to a pattern detection/non-detection control unit (130) as a control signal (CTL) when the hit signal (HIT) is outputted. The pattern detection/non-detection control unit (130) outputs a holding enable signal (HEB) for holding data showing a position of detected data in accordance with the hit signal (HIT) and the control signal (CTL).